Issue with score: incorrect value?

I've noticed a strange issue with how score is handled in bAtari BASIC. I've noticed that in one of my old games, and especially my new one, that once the score increases over 999, it shoots up to 101000. This trend continues, where the 6th digit is equal to the 4th digit. This also is not counted as a score higher than one lower than it, as my high score is unchanged after restarting. I do nothing special in my code, except statements such as score = score + 1. What is causing this issue, and can I fix it?

It's an issue with the bB score display and the flashback portable. It even affects a couple of the games included with it (Strip Off and Shield Shifter). Nukey Shay made fixed versions of those 2 games, but as far as I know, no one has made any changes to bB or the flashback emulator to fix the problem. The score does display properly on a real 2600 though.